Fixes #240 - Clone operation highlights changes correctly

The clone operation no longer flags edits as errors. This looks better.

Fixes #132 - Added a clone operation

This clones the AR, attaches clones of the
originals host_parameters and then renders the "new" action, ready for editing.

The host_parameters must not use validate_presence of :host_id when using nested attributes.
Created a hidden :nested attribute to the form to flag this behaviour...

• Remove active scaffold from hosts controller.
• changed default host graphs from one day for up to one week
• added dynamic dropdown boxes for host creation / edit page (e.g. for puppet classes, operating systems etc)....